1. Field of the Invention
The present invention relates generally to an apparatus with a touch screen and a method for displaying information on a screen of an external display device connected thereto, and in particular, to an apparatus and method for enabling a touch screen to serve as a mouse pad.
2. Description of the Related Art
A touch screen has a user interface function as well as a screen displaying function. That is, when a user, using a touch screen pen (i.e. stylus) or his or her finger, writes letters or symbols, or draws a picture on an LCD (Liquid Crystal Display) covered with a touch panel using the touch screen pen, a pointer shifts along the moving path selected by the user. If the user touches an icon displayed on the screen in a specific mode, a relevant function is performed, and at the same time, its operating state may be displayed on the screen.
A PDA (Personal Digital Assistant) is generally provided with the touch screen. The PDA is a portable device capable of collecting, storing, writing and searching information and also performing a communication function. The PDA is very useful to access personal and company information while on the move, for its small size and light weight. The PDA includes a CPU (Central Processing Unit), a memory, an operating system (OS), and various peripheral devices based on the operating system. Typically, a touch screen LCD and a pen are used as an input device of the PDA.
However, the PDA is limited in size, and therefore the touch screen mounted on the PDA is also small in size. Therefore, it is hard to display all the contents wanted by the user on the touch screen. To solve this problem, the user may connect the PDA to an external display device with a large screen capable of clearly displaying more content or information. The user can also manipulate arrow buttons mounted on the PDA, or manipulate an externally connected keyboard, in order to further control a program operating on the external display device, e.g., an operation of scrolling the screen, moving the pointer, and inputting a command.